Emergency rescue personnel (principally firefighters, and military and law enforcement personnel) may encounter conditions requiring a very rapid egress from a building or other structure at height. When trapped in a structure above ground level and in urgent need of getting to ground, but when having no reasonable means to descend to ground level in a customary manner (stairs, elevators, and the like), it is desirable to have equipment that provides for a safe descent in a non-customary manner—such as by jumping from a window. To be able to do so safely in urgent circumstances is an answer to prayer; to have those prayers answered in advance is the object of the present invention.
In principle, all descent control devices (aka “descenders”) use friction in one or another manner to control the rate of descent when using a rope to lower equipment or people. Broadly, there are two categories of descenders, namely variable friction and fixed friction, and three types: (1) figure eights, a fixed friction device commonly used for short drops and use in bottom belays, but prone to put kinks and twists in rope; (2) racks, which are variable friction devices which resemble a miniature ladder, most useful for very long descents but significantly bulkier and heavier than figure eights and thus not well suited for emergency use by first responders; and (3) bobbins, almost universally associated with popularized by its French caving gear producer, Petzl. Bobbins are constant friction descenders using bollards over which rope is threaded in a sinuous pattern to create a friction angle of about 480°. Newer models may include a rope brake that can be actuated to apply stopping force friction during a descent. Belay plates and Munter hitches are also popular. There are basically three types of descent devices:
Type 1—Hand Brake/Hand Control Descent: User must hold onto the rope with this device to brake and to control their decent. If not, they will fall to the ground.
Type 2—Auto Brake/Hand Control Descent: User does not need to hold onto the device when exiting a window, the device will auto brake for them. When the device is manipulated in some fashion via a lever or motion, the rope will be free to move depending on the user controlling the rope release.
Type 3—Auto Brake/Auto Control Descent: User does not need to hold onto device when exiting a window, the device will break for them. The device can be also set to descend at a set rate of speed, no need for the user to control the rope.
The present invention (which bears the proprietary name of the “Core”) is a Type 2 Auto Brake/Hand Control Device. It is an auto braking descent device that brakes without any help from the user. The unique feature of the Core is that it does not use any moving parts to make the auto breaking work. The absence of moving parts prevents damage and operational failure in the presence of debris, dirt, sand, or other potential impediments are present, such as are commonly found in firefighter and military activities and environments. It is the first to use gravity alone—i.e., the user's weight and threading of the rope into the device—to accomplish the auto breaking.
Auto Brake/Hand Control Devices are popular among firefighters because firefighters were heavy protective firefighter gloves and are often unable to feel and locate the free end of the rope during an emergency exit. This is because firefighter gloves are bulky and lack flexibility, and dramatically decrease tactile awareness. Also, the inability to see clearly through a safety facemask, such as those worn by firefighters, limits the ability the see and to easily find and use the free end of the rope. Time is short in emergency situations, and just getting an anchor established is the only action one can accomplish prior to making an emergency jump from a window or roof. The Core catches the firefighter (stops freefall) once out the window, and the firefighter can then locate the handle and control the descent. Once out of the hazardous environment, the firefighter can locate the free end of the rope and manipulate the Core to complete a descent.
Military personnel encounter similar problems, particularly when lowering from a helicopter and under fire. The Core will not allow a user to fall to the ground if wounded and disabled, and the user can thus be flown to a safer location. Again, the absence of failure-prone moving parts allows for a higher degree of safety. In contrast, when using a Type 1 descent device, the user would simply fall to the ground. And Type 3 devices are simply large, costly, and have several failure-prone moving parts that jam with debris.
Existing descenders work sufficiently well in most commercial and recreational applications. But for the emergency first responder, an extremely high quality descent control device is required. This is particularly true because when intended for use by firefighters, descent control devices must meet extremely stringent standards set by the National Fire Protection Association (“NFPA”). Specifically, the NFPA 1983 (amended 2012) Escape “E” standards for Descent Control Device Performance Requirements of 3 σ MBS of not less than 13.5 kN (3,034 lbf). Under a load test, the descent control device must not allow rope to slide through the device when locked off under a load of 300+ lbs. However, when the user wishes for rope to be paid out, when rope is released for free payout, the payout must occur at less than 20 lbs of applied force. NFPA 1983 standards also require that ropes must have strength, static, and stretch characteristics that will not allow them to break under a tensile load of 3,000 lbs, and many descent control devices will actually cause rope failure under such tensile loads.
The present invention is a descent control device that meets and exceeds all NFPA 1983 standards for descent control hardware. It is lightweight, simple to use, self-righting, absolutely reliable, and perfectly adapted for firefighters, rescuers, and military and law enforcement personnel. Importantly, the descender is exceedingly simple to use, intuitive in every respect, and as a critical safety component is configured to immediately lock upon release when under load. When not under load, rope properly threaded through the hole configuration easily pays out horizontally, when, for instance, a firefighter is mapping a path through a smoke-filled structure using a tethered safety line.